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460 BCE
Democritus
Democritus had the theory that all things were made of super small units called atoms. He said that they are everywhere -
John Dalton
He said that all things were made of atoms and that if 2 of them combined that they made a compound. He believed that they were indestructible. -
Dmitri Mendeleev
He created the Periodic Table. -
Eugene Goldstein
He discovered positive particles and he realized that each positive electron had a negative charge. -
J.J. Thomson
He discovered electrons. He also discovered electric discharges by using a high vacuum cathode-ray tube -
Ernest Rutherford
He used the gold experiment and then he shot alpha particles through it then most of them went through the gold foil which tells us that most of the mass of an atom is concentrated into a small area. -
Milikan
Determined how to determine the charge of electrons -
Neils Bohr
Discovered that electrons orbited nucleus in atoms -
Planck
Created the quantum theory -
Heisenberg
Created the Uncertainty Principle:
- You can never know the exact location of an electron
- You can never know the exact amount of energy it produces -
James Chadwick
He bombarded beryllium atoms with alpha particles. He found a unknown radiation which was the nuetron -
Erwin Schrodinger
He created an equation for tracking electron movements.
